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Patented May 20, 1930 UNITED STATES PATENT orFica RALPH P. DE .VBIEB, OI NEWTONVILLE, NEW YORK, ABBIGNOB- TO LUDLUI STEEL Oil WATERVLIET, NEW YORK, A CORPORATION OF NEW JERSEY.

STABLE-SURFACE ALLOY STEEL 1T0 Drawing.

This inventionrelates to alloys of steel,

4 and more particularly to such alloys as are known to the trade as stable-surface alloy Steels.

5 The main objects of m invention are to provide an alloy steel 0 new composition which will be resistant to scaling action at high temperatures ranging from a low red heat to temperatures as high as 1800 F., and

which will be resistant in varying degrees to rusting-acids and corroding agents of various kinds. This steel may be readily forged and rolled, and when it has been thus forged and rolled, it will have good strength and fair ductility.

The invention is especially useful where steels are to be used for internal combustion engine poppet valves, electrical resistance heating elements, carburizing boxes, and for other purposes wherein metal is desired which will resist scaling, particularly to high temperatures.

I have discovered that copper, silicon, and aluminum may be alloyed with steel in such proportions as to produce a high degree of resistance to scaling at high temperatures. It is essential that such an alloy have good physical properties as regards strength and malleability. Copper when used with silicon and aluminum, in the ranges hereinafter set forth, produces in this alloy the desired amount of strength and malleability and at the same time gives to this alloy a high degree of resistance to scaling at high temperatures.

An alloy steel made in accordance with my invention contains silicon from 0.1% to 6.0%, aluminum from 0.1% to 6.0%, and copper from 0.5% to 5.0%. I have found that for good results the silicon and aluminum taken together must never be less than 2.0%, and for best results not more than 6.1% of the total alloy. I have further discovered that when the silicon and aluminum content taken together is raised to any point above 2.5% it is desirable that the amount of copper be not less than 1.0%, and when the alloy containing over 2.5% of silicon and aluminum combined is to be used, it is necessary for many purposes to add at least 3% to 4% of copper.

5 Alloys of this composition can be melted Application fled January 20, 1926. serial No. 82,608.

practically carbon free but for some purposes may contain carbon as high as 1.0%. The usual amount of manganese found in tool and structural steels may be present, or slightly reater amounts up to 1.5% may be used.

mpurities and metalloids such as sulphur, phosphorus, etc, will be kept as low as posslble. Typical examples of this alloy may be noted as having the following composition, 1t being understood that the iron balance may include the manganese, impurities and metalloids mentioned above:

Silicon g Copper Carbon Iron l 3.50% 0.50% a. 00% 025;, Balance. a00% 0.25% 1.00% 0. s2 Balance. 2.50% 1.25% 2.50% 0.40% Balance.

the oxide film which is formed is generally bright even when exposed to sharply oxidizing flames. This color adds materially to the commercial possibilities of this alloy as it gives more striking evidence of its scale resisting qualities than when an alloy becomes black in color. For still further refining the grain, titanium may be added in amounts running from as low as 0.1% up to 5.0%. When titanium is added, the copper content may be as high as 10%. Where it is desired to impart to the alloy which is to be subjected to high temperatures, greater strength at high temperatures, I may add tungsten or molybdenum in percentages 0.5% to 5.0%, to o ain additional strength at high temperatures.

Alloy steels made in accordance with my invention can be readily hardened by heating above their critical ranges and then cooling in water, oil, or air as desired. For many purposes for which this alloy steel is adapted, it will be desirable to vary the physical properties b heat treatment which may consist of ha ening as mentioned and drawing the steel by re-heating after such "hardemng. .4

I claam- 1 1. A ferrous alloy containing from 0.5% to 5% copper; from 0.5% to6% silicon together with from 0.1% to 2% aluminum, and

10 characterized by its resistance to scaling and corrosion at high temperatures.

2. A stable surface alloy steel comprising about from 0.5 to 6% of silicon, about from 0.1 to 6% of aluminum and about from 0.5

to 5% of copper.

3. A stable surface ferrous alloy com rising about 0.5 to 6% of silicon, about rom 0.1 to 6% of aluminum, the total of the silicon and aluminum being between 2% and 6.1%

and about 0.5 to 5% of copper.

4. A stable surface ferrous alloy com risprising about from 0.5 to 6% of SllICOll, about from 0.1 to 6% of aluminum, the total of the silicon and aluminum being between 2.5% and 6% and about 1 to 5% of copper.

5. A stable surface ferrous alloy com ris-' I ing about from 0.5 to-6% of silicon, a out 0.1 to 6% of aluminum, about from 1 to 10% of copper and about 0.1 to 5% of titanium.

In testimony whereof I have signed my name to this specification.

RALPH P. DE VRIES. 

